Electrolysis of water



Mar. 13,1923. 1,448,037.

R. PECHKRANZ.

ELECTROLYSIS OF WATER.

FILED JULY 12, 1922.

EL ECTIFODES I Patented Mar. 13, 1923..

RODOLPHE PECHKRAN Z, OF GENEVA, SWITZERLAND.

ELEo'rRoLYsIs or WATER.

Application filed July 12, 1922. Serial No. 574,482;

Switzerland, have invented certain new and useful Improvements in or Relating to the Electrolysis of Water, of which the follow- 4 ing is a specification. H

The use of metallic partitions in apparatus for the electrolysis of water is well known.

Their advantages in comparison with the customary, usual mineral partitions can however, as careful study and exhaustive experiments have shown, only be properly developed in the case of water decomposing apparatuses built on the filter press principle, if the metallic partitions be made as extremely thin and finely perforated.

Whereas the great advantage of very thin metal partitions has been hitherto unknown, attention has. on the other hand already been directed to the use of a small perforation, though not for extremely thin metal partitions it is true. It was absolutely necessary found however that it was to restrict these small perforations to a few centimetres above the lower edge of the electrodes, so as to prevent mixture of the gases.

A more general perforationappeared formerly to lead to very extensive defects, as there was risk that not only the electrolyte, but also the gas evolved would be allowed to pass through.

These previously known types of construction involve compared with those according to the present invention a great waste of material, current and amount of space occupied.

The water decomposer according to the present invention is built on the filter press principle, with electrodes of thin sheet metal, the partitions which are arranged between the electrodes and which are likewise of metal, being made extremely thin and perforated with very fine holes, so that at most only a fractional part of their total surface is left solid. 1

In the accompanying drawing is diagrammatically illustrated by way of example a constructional form of the apparatus and detail modifications.

I filter Figs. 1 and 2 are an elevation anda plan respectively of the constructional form. Fig. 3 is an elevation of an electrode.

-Figs. 4 and 5 are two vertical sections, at

-right angles to each other, through this constructional form, and on a larger scale.

Figs. 6 and 7 show detail modifications. As shown in Figs. 1 and 2 this constructional form has aframe a, which consists of.

four standards a and a frame a on which latter the elements of the apparatus rest. By means of a screw 6, the elements, which are clampedbetween the cast plates 0,11, arranged at both ends of the apparatus, can be pressed very strongly against each other, so that the general arrangement of this apparatus corresponds to that of an ordinary press.

The electrodes e are made of thin sheet metal, the thickness of which is shown on a very exaggerated scale in the drawing, and may amount to a fractional part of millimetre, are of rectangular form (see Fig. 3) and are arranged between frames 7 (see Figs. 4 and 5). The electrodes 6 are simply held by pressure and friction in the correct partitions is however solid, in order to prevent .thetwo gases from diffusing into each other, whereby large bubbles of gas might-collect. V

The partitions 9 may be made for ex- -ample of a thin sheet of pure nickel or a metal belonging to the nickel group, which has been obtained by'electrolysis, or they may consist only of pure nickel in preponderance. Such partitions secure uninterrupted working, as it is not necessary to'remove them from the apparatus from time to time. 1

The frames f are supportedby means of lugs f on the frames a? and are provided on both their side surfaces with a groovef which runs. all round them and in which a strip or band of some compressible material, for example rubber, is laid so as to provide a packing between the frame 7 and the electrode a. At the four corners of the rectangular frames f are provided holes 7, f f, f", which are situated at right angles to the plane of the: frames and run from end to end of the apparatus, and which form .With corresponding holes e 6*, 6 e pierced in the electrodes 6 passages which run throughout the entire length of the apparatus. In addition to this the holes f, f, f are each connected by holes 7, f f f which are arranged parallel with the plane of the frame, to one of the two spaces which exist on both sides of an electrode 6. At one end the passage e 3 communicates by a. pipe 71 with a gas separator j in which for example the separation of the hydrogen from the .gaselectrolyte emulsion takes place. One end of the passage e is also connected by a. pipe to a second gas separator 74 which is provided for the separation of the oxygen from the. gas electrolyte emulsion, for example. The electrolyte, which is separated in the gas separator 7' from the hydrogen, flows through the pipe Z and the passage 6 f back into the space on the right hand of the electrode e from which it originated.

'. In the same way the electrolyte flows out of the gas separator 10 through the pipe m and the passage vef into the spaces on the left'ofthe electrodes 6 from which it escaped as an emulsion with the gasthrough thepassage e When a solution of caustic potash is used as the electrolyte, the gas bubbles separate somewhat more slowly than they do when the potassium carbonate solution now customary is employed, so that itis advantageous to return the electrolyte which runs back, to each of the spaces from which -it came, and not, as is usual, to return those portions of the electrolyte which issue from the difierent spaces, to all these spaces in a mixed state.

- The purity of the gases obtained is thereby augmented. On the other hand an unequal concentration of the electrolyte in the two groups of frames owing to unequal wandering of'the ions, is not to be feared as the metallic partitions 9 allow for thorough mixing.

The electrodes e are separated from the frames a by an insulating layer a, so that they are not connected in parallel across it, which means that no trace of any separation of gas can be detected at the partitions 9 so long asdouble the water decomposing voltage is not available ,per element.

As shown in Fig. 6 the electrodes e are larger than the frames f, so that they have the electrodes. In this illustration the electrodes and the frames are shown in the position which they occupy before they are pressed together.

It is obvious of course that the holes provided for the formation of the longitudinal passages may also be arranged outside the frame.

Having now particularly described and ascertained the nature 'of the said invention and in what manner the same is to be performed, I declare that what I claim is 1. A water decomposing apparatus of the filter press type comprising electrodes formed of thinsheet metal, extremely thin partitions formed of metal arranged between said electrodes, said partitions being provided over substantially their total surface, with extremely minute perforations.

2. A water decomposing apparatus of the filter press type comprising,' electrodes formed of thin sheet metal, extremely thin partitions consisting essentially of nickel and arranged between said electrodes, said partitions being provided over the greater part of their entire surface, with very fine perforations. a I

3. A water decomposing apparatus of the filter press type comprising, electrodes formed of thin sheet metal, very thin metal partitions arranged between said electrodes, said partitions being provided over the greater part of their entire surface, with very fine perforations, frames of insulating material receiving said partition and being provided with a number of longitudinal passages, holes in the electrodes to correspond with the passages, said passages each being connected by holes arranged parallel with the plane of the frame, to one of two spaces which exists on each side of the partitions.

4. A water decomposing apparatus of the filter press type comprising, electrodes formed of thin sheet metal, very thin metal partitions and arranged between said elec trodes, said partitions being provided over the major part of their entire surface,

with very fine perforations, rectangular.

formed of thin sheet metal, very thin metal partitions arranged between said, electrodes, said partitions being provided over 1130 the v,ggreater part of their surface, with very In testimony whereof I have afiixed my fine perforations,- frames of insulatiilngl'J masignature in presence of two Witnesses.

terial receivin said artitions an ein positioned ad-jagcent thg electrodes said ele RODOLPHE PECHKR'ANZ' 5 trodes being so dimensioned as to project out Witnesses:

beyond the frames, whereby their projecting R01). DE WURTEMBERG,

part serves for cooling the electrolyte. EDM. EMMANUEL. 

